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Diffstat (limited to 'libraries/ieee/math_real-body.vhdl')
| -rw-r--r-- | libraries/ieee/math_real-body.vhdl | 230 |
1 files changed, 108 insertions, 122 deletions
diff --git a/libraries/ieee/math_real-body.vhdl b/libraries/ieee/math_real-body.vhdl index c20aab7c9..2386f82fa 100644 --- a/libraries/ieee/math_real-body.vhdl +++ b/libraries/ieee/math_real-body.vhdl @@ -1,53 +1,52 @@ ------------------------------------------------------------------------- +-- ----------------------------------------------------------------- +-- +-- Copyright 2019 IEEE P1076 WG Authors +-- +-- See the LICENSE file distributed with this work for copyright and +-- licensing information and the AUTHORS file. +-- +-- This file to you under the Apache License, Version 2.0 (the "License"). +-- You may obtain a copy of the License at +-- +-- http://www.apache.org/licenses/LICENSE-2.0 +-- +-- Unless required by applicable law or agreed to in writing, software +-- distributed under the License is distributed on an "AS IS" BASIS, +-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or +-- implied. See the License for the specific language governing +-- permissions and limitations under the License. -- --- Copyright 1996 by IEEE. All rights reserved. - --- This source file is an informative part of IEEE Std 1076.2-1996, IEEE Standard --- VHDL Mathematical Packages. This source file may not be copied, sold, or --- included with software that is sold without written permission from the IEEE --- Standards Department. This source file may be used to implement this standard --- and may be distributed in compiled form in any manner so long as the --- compiled form does not allow direct decompilation of the original source file. --- This source file may be copied for individual use between licensed users. --- This source file is provided on an AS IS basis. The IEEE disclaims ANY --- WARRANTY EXPRESS OR IMPLIED INCLUDING ANY WARRANTY OF MERCHANTABILITY --- AND FITNESS FOR USE FOR A PARTICULAR PURPOSE. The user of the source --- file shall indemnify and hold IEEE harmless from any damages or liability --- arising out of the use thereof. - --- --- Title: Standard VHDL Mathematical Packages (IEEE Std 1076.2-1996, --- MATH_REAL) --- --- Library: This package shall be compiled into a library --- symbolically named IEEE. --- --- Developers: IEEE DASC VHDL Mathematical Packages Working Group --- --- Purpose: This package body is a nonnormative implementation of the --- functionality defined in the MATH_REAL package declaration. --- --- Limitation: The values generated by the functions in this package may --- vary from platform to platform, and the precision of results --- is only guaranteed to be the minimum required by IEEE Std 1076 --- -1993. --- --- Notes: --- The "package declaration" defines the types, subtypes, and --- declarations of MATH_REAL. --- The standard mathematical definition and conventional meaning --- of the mathematical functions that are part of this standard --- represent the formal semantics of the implementation of the --- MATH_REAL package declaration. The purpose of the MATH_REAL --- package body is to clarify such semantics and provide a --- guideline for implementations to verify their implementation --- of MATH_REAL. Tool developers may choose to implement --- the package body in the most efficient manner available to them. --- --- ----------------------------------------------------------------------------- --- Version : 1.5 --- Date : 24 July 1996 --- ----------------------------------------------------------------------------- +-- Title : Standard VHDL Mathematical Packages +-- : (MATH_REAL package body) +-- : +-- Library : This package shall be compiled into a library +-- : symbolically named IEEE. +-- : +-- Developers: IEEE DASC VHDL Mathematical Packages Working Group +-- : +-- Purpose : This package defines a standard for designers to use in +-- : describing VHDL models that make use of common REAL +-- : constants and common REAL elementary mathematical +-- : functions. +-- : +-- Limitation: The values generated by the functions in this package +-- : may vary from platform to platform, and the precision +-- : of results is only guaranteed to be the minimum required +-- : by IEEE Std 1076-2008. +-- : +-- Note : This package may be modified to include additional data +-- : required by tools, but it must in no way change the +-- : external interfaces or simulation behavior of the +-- : description. It is permissible to add comments and/or +-- : attributes to the package declarations, but not to change +-- : or delete any original lines of the package declaration. +-- : The package body may be changed only in accordance with +-- : the terms of Clause 16 of this standard. +-- : +-- -------------------------------------------------------------------- +-- $Revision: 1220 $ +-- $Date: 2008-04-10 17:16:09 +0930 (Thu, 10 Apr 2008) $ +-- -------------------------------------------------------------------- package body MATH_REAL is @@ -101,7 +100,7 @@ package body MATH_REAL is FLAG := TRUE; end loop; return V; - end POWER_OF_2_SERIES; + end function POWER_OF_2_SERIES; constant TWO_AT_MINUS : REAL_VECTOR := POWER_OF_2_SERIES( @@ -183,7 +182,7 @@ package body MATH_REAL is end loop; end if; return REAL_ARR_3'(X, Y, Z); - end CORDIC; + end function CORDIC; -- -- Bodies for Global Mathematical Functions Start Here @@ -201,7 +200,7 @@ package body MATH_REAL is else return 0.0; end if; - end SIGN; + end function SIGN; function CEIL (X : in REAL ) return REAL is -- Description: @@ -240,7 +239,7 @@ package body MATH_REAL is return RD; end if; end if; - end CEIL; + end function CEIL; function FLOOR (X : in REAL ) return REAL is -- Description: @@ -279,7 +278,7 @@ package body MATH_REAL is return RD; end if; end if; - end FLOOR; + end function FLOOR; function ROUND (X : in REAL ) return REAL is -- Description: @@ -297,7 +296,7 @@ package body MATH_REAL is else return 0.0; end if; - end ROUND; + end function ROUND; function TRUNC (X : in REAL ) return REAL is -- Description: @@ -315,7 +314,7 @@ package body MATH_REAL is else return 0.0; end if; - end TRUNC; + end function TRUNC; @@ -326,8 +325,8 @@ package body MATH_REAL is -- Notes: -- a) Returns 0.0 on error - variable XNEGATIVE : BOOLEAN := X < 0.0; - variable YNEGATIVE : BOOLEAN := Y < 0.0; + constant XNEGATIVE : BOOLEAN := X < 0.0; + constant YNEGATIVE : BOOLEAN := Y < 0.0; variable VALUE : REAL; begin -- Check validity of input arguments @@ -354,7 +353,7 @@ package body MATH_REAL is end if; return VALUE; - end "MOD"; + end function "MOD"; function REALMAX (X, Y : in REAL ) return REAL is @@ -369,7 +368,7 @@ package body MATH_REAL is else return Y; end if; - end REALMAX; + end function REALMAX; function REALMIN (X, Y : in REAL ) return REAL is -- Description: @@ -383,7 +382,7 @@ package body MATH_REAL is else return Y; end if; - end REALMIN; + end function REALMIN; procedure UNIFORM(variable SEED1,SEED2:inout POSITIVE;variable X:out REAL) @@ -438,7 +437,7 @@ package body MATH_REAL is SEED1 := POSITIVE'(TSEED1); SEED2 := POSITIVE'(TSEED2); X := REAL(Z)*4.656613e-10; - end UNIFORM; + end procedure UNIFORM; @@ -490,7 +489,7 @@ package body MATH_REAL is COUNT := COUNT + 1; end loop; return NEWVAL; - end SQRT; + end function SQRT; function CBRT (X : in REAL ) return REAL is -- Description: @@ -503,7 +502,7 @@ package body MATH_REAL is variable INIVAL: REAL; variable XLOCAL : REAL := X; - variable NEGATIVE : BOOLEAN := X < 0.0; + constant NEGATIVE : BOOLEAN := X < 0.0; variable OLDVAL : REAL ; variable NEWVAL : REAL ; variable COUNT : INTEGER := 1; @@ -545,7 +544,7 @@ package body MATH_REAL is end if; return NEWVAL; - end CBRT; + end function CBRT; function "**" (X : in INTEGER; Y : in REAL) return REAL is -- Description: @@ -588,7 +587,7 @@ package body MATH_REAL is -- Get value for general case return EXP (Y * LOG (REAL(X))); - end "**"; + end function "**"; function "**" (X : in REAL; Y : in REAL) return REAL is -- Description: @@ -631,7 +630,7 @@ package body MATH_REAL is -- Get value for general case return EXP (Y * LOG (X)); - end "**"; + end function "**"; function EXP (X : in REAL ) return REAL is -- Description: @@ -649,7 +648,7 @@ package body MATH_REAL is -- constant EPS : REAL := BASE_EPS*BASE_EPS*BASE_EPS;-- Precision criteria - variable RECIPROCAL: BOOLEAN := X < 0.0;-- Check sign of argument + constant RECIPROCAL: BOOLEAN := X < 0.0;-- Check sign of argument variable XLOCAL : REAL := ABS(X); -- Use positive value variable OLDVAL: REAL ; variable COUNT: INTEGER ; @@ -733,7 +732,7 @@ package body MATH_REAL is end if; return NEWVAL; - end EXP; + end function EXP; -- @@ -767,7 +766,7 @@ package body MATH_REAL is N := N -1; end loop; return N; - end ILOGB; + end function ILOGB; function LDEXP(X: in REAL; N: in INTEGER) RETURN REAL IS -- Description: @@ -776,7 +775,7 @@ package body MATH_REAL is -- None begin return X*(2.0 ** N); - end LDEXP; + end function LDEXP; function LOG (X : in REAL ) return REAL IS -- Description: @@ -796,11 +795,7 @@ package body MATH_REAL is -- 2. Redistributions in binary form must reproduce the above copyright -- notice, this list of conditions and the following disclaimer in the -- documentation and/or other materials provided with the distribution. - -- 3. All advertising materials mentioning features or use of this - -- software must display the following acknowledgement: - -- This product includes software developed by the University of - -- California, Berkeley and its contributors. - -- 4. Neither the name of the University nor the names of its + -- 3. Neither the name of the University nor the names of its -- contributors may be used to endorse or promote products derived -- from this software without specific prior written permission. -- @@ -1103,8 +1098,6 @@ package body MATH_REAL is variable M, J:INTEGER; variable F1, F2, G, Q, U, U2, V: REAL; - variable ZERO: REAL := 0.0;--Made variable so no constant folding occurs - variable ONE: REAL := 1.0; --Made variable so no constant folding occurs -- double logb(), ldexp(); @@ -1171,7 +1164,7 @@ package body MATH_REAL is U2 := (U2 + LOGF_TAIL(J)) + Q; -- Tiny U2 := U2 + LOGF_TAIL(N)*REAL(M); return (U1 + U2); - end LOG; + end function LOG; function LOG2 (X: in REAL) return REAL is @@ -1199,7 +1192,7 @@ package body MATH_REAL is -- Compute value for general case return ( MATH_LOG2_OF_E*LOG(X) ); - end LOG2; + end function LOG2; function LOG10 (X: in REAL) return REAL is @@ -1227,7 +1220,7 @@ package body MATH_REAL is -- Compute value for general case return ( MATH_LOG10_OF_E*LOG(X) ); - end LOG10; + end function LOG10; function LOG (X: in REAL; BASE: in REAL) return REAL is @@ -1262,7 +1255,7 @@ package body MATH_REAL is -- Compute value for general case return ( LOG(X)/LOG(BASE)); - end LOG; + end function LOG; function SIN (X : in REAL ) return REAL is @@ -1280,7 +1273,7 @@ package body MATH_REAL is constant EPS : REAL := BASE_EPS*BASE_EPS; -- Convergence criteria variable N : INTEGER; - variable NEGATIVE : BOOLEAN := X < 0.0; + constant NEGATIVE : BOOLEAN := X < 0.0; variable XLOCAL : REAL := ABS(X) ; variable VALUE: REAL; variable TEMP : REAL; @@ -1293,10 +1286,8 @@ package body MATH_REAL is end if; if XLOCAL < 0.0 then - assert FALSE - report "XLOCAL <= 0.0 after reduction in SIN(X)" - severity ERROR; - XLOCAL := -XLOCAL; + -- adjust for rounding error + XLOCAL := 0.0; end if; -- Compute value for special cases @@ -1413,7 +1404,7 @@ package body MATH_REAL is -- Compute value for general cases if ((XLOCAL < MATH_PI_OVER_2 ) and (XLOCAL > 0.0)) then - VALUE:= CORDIC( KC, 0.0, x, 27, ROTATION)(1); + VALUE:= CORDIC( KC, 0.0, X, 27, ROTATION)(1); end if; N := INTEGER ( FLOOR(XLOCAL/MATH_PI_OVER_2)); @@ -1435,7 +1426,7 @@ package body MATH_REAL is else return VALUE; end if; - end SIN; + end function SIN; function COS (X : in REAL) return REAL is @@ -1452,7 +1443,6 @@ package body MATH_REAL is constant EPS : REAL := BASE_EPS*BASE_EPS; variable XLOCAL : REAL := ABS(X); - variable VALUE: REAL; variable TEMP : REAL; begin @@ -1463,10 +1453,8 @@ package body MATH_REAL is end if; if XLOCAL < 0.0 then - assert FALSE - report "XLOCAL <= 0.0 after reduction in COS(X)" - severity ERROR; - XLOCAL := -XLOCAL; + -- adjust for rounding error + XLOCAL := 0.0; end if; -- Compute value for special cases @@ -1511,7 +1499,7 @@ package body MATH_REAL is -- Compute value for general cases return SIN(MATH_PI_OVER_2 - XLOCAL); - end COS; + end function COS; function TAN (X : in REAL) return REAL is -- Description: @@ -1522,7 +1510,7 @@ package body MATH_REAL is -- c) Returns REAL'LOW on error if X < 0.0 -- d) Returns REAL'HIGH on error if X > 0.0 - variable NEGATIVE : BOOLEAN := X < 0.0; + constant NEGATIVE : BOOLEAN := X < 0.0; variable XLOCAL : REAL := ABS(X) ; variable VALUE: REAL; variable TEMP : REAL; @@ -1535,10 +1523,8 @@ package body MATH_REAL is end if; if XLOCAL < 0.0 then - assert FALSE - report "XLOCAL <= 0.0 after reduction in TAN(X)" - severity ERROR; - XLOCAL := -XLOCAL; + -- adjust for rounding error + XLOCAL := 0.0; end if; -- Check validity of argument @@ -1576,7 +1562,7 @@ package body MATH_REAL is else return VALUE; end if; - end TAN; + end function TAN; function ARCSIN (X : in REAL ) return REAL is -- Description: @@ -1585,8 +1571,8 @@ package body MATH_REAL is -- a) ARCSIN(-X) = -ARCSIN(X) -- b) Returns X on error - variable NEGATIVE : BOOLEAN := X < 0.0; - variable XLOCAL : REAL := ABS(X); + constant NEGATIVE : BOOLEAN := X < 0.0; + constant XLOCAL : REAL := ABS(X); variable VALUE : REAL; begin @@ -1621,7 +1607,7 @@ package body MATH_REAL is end if; return VALUE; - end ARCSIN; + end function ARCSIN; function ARCCOS (X : in REAL) return REAL is -- Description: @@ -1630,8 +1616,8 @@ package body MATH_REAL is -- a) ARCCOS(-X) = MATH_PI - ARCCOS(X) -- b) Returns X on error - variable NEGATIVE : BOOLEAN := X < 0.0; - variable XLOCAL : REAL := ABS(X); + constant NEGATIVE : BOOLEAN := X < 0.0; + constant XLOCAL : REAL := ABS(X); variable VALUE : REAL; begin @@ -1665,7 +1651,7 @@ package body MATH_REAL is end if; return VALUE; - end ARCCOS; + end function ARCCOS; function ARCTAN (Y : in REAL) return REAL is @@ -1678,7 +1664,7 @@ package body MATH_REAL is constant EPS : REAL := BASE_EPS*BASE_EPS*BASE_EPS; - variable NEGATIVE : BOOLEAN := Y < 0.0; + constant NEGATIVE : BOOLEAN := Y < 0.0; variable RECIPROCAL : BOOLEAN; variable YLOCAL : REAL := ABS(Y); variable VALUE : REAL; @@ -1733,7 +1719,7 @@ package body MATH_REAL is end if; return VALUE; - end ARCTAN; + end function ARCTAN; function ARCTAN (Y : in REAL; X : in REAL) return REAL is @@ -1786,7 +1772,7 @@ package body MATH_REAL is end if; return VALUE; - end ARCTAN; + end function ARCTAN; function SINH (X : in REAL) return REAL is @@ -1796,8 +1782,8 @@ package body MATH_REAL is -- a) Returns (EXP(X) - EXP(-X))/2.0 -- b) SINH(-X) = SINH(X) - variable NEGATIVE : BOOLEAN := X < 0.0; - variable XLOCAL : REAL := ABS(X); + constant NEGATIVE : BOOLEAN := X < 0.0; + constant XLOCAL : REAL := ABS(X); variable TEMP : REAL; variable VALUE : REAL; @@ -1816,7 +1802,7 @@ package body MATH_REAL is end if; return VALUE; - end SINH; + end function SINH; function COSH (X : in REAL) return REAL is -- Description: @@ -1825,7 +1811,7 @@ package body MATH_REAL is -- a) Returns (EXP(X) + EXP(-X))/2.0 -- b) COSH(-X) = COSH(X) - variable XLOCAL : REAL := ABS(X); + constant XLOCAL : REAL := ABS(X); variable TEMP : REAL; variable VALUE : REAL; begin @@ -1840,7 +1826,7 @@ package body MATH_REAL is VALUE := (TEMP + 1.0/TEMP)*0.5; return VALUE; - end COSH; + end function COSH; function TANH (X : in REAL) return REAL is -- Description: @@ -1849,8 +1835,8 @@ package body MATH_REAL is -- a) Returns (EXP(X) - EXP(-X))/(EXP(X) + EXP(-X)) -- b) TANH(-X) = -TANH(X) - variable NEGATIVE : BOOLEAN := X < 0.0; - variable XLOCAL : REAL := ABS(X); + constant NEGATIVE : BOOLEAN := X < 0.0; + constant XLOCAL : REAL := ABS(X); variable TEMP : REAL; variable VALUE : REAL; @@ -1869,7 +1855,7 @@ package body MATH_REAL is else return VALUE; end if; - end TANH; + end function TANH; function ARCSINH (X : in REAL) return REAL is -- Description: @@ -1885,7 +1871,7 @@ package body MATH_REAL is -- Compute value for general cases return ( LOG( X + SQRT( X*X + 1.0)) ); - end ARCSINH; + end function ARCSINH; @@ -1912,7 +1898,7 @@ package body MATH_REAL is -- Compute value for general cases return ( LOG( X + SQRT( X*X - 1.0))); - end ARCCOSH; + end function ARCCOSH; function ARCTANH (X : in REAL) return REAL is -- Description: @@ -1936,6 +1922,6 @@ package body MATH_REAL is -- Compute value for general cases return( 0.5*LOG( (1.0+X)/(1.0-X) ) ); - end ARCTANH; + end function ARCTANH; -end MATH_REAL; +end package body MATH_REAL; |